Previous research in this Laboratory has examined personality profiles of cultures obtained by averaging traits assessed in samples of college students and adults. We have extended this line of research by examining ratings of 12 to 17 years old in 24 cultures. Observer ratings of adolescents were obtained using the NEO Personality Inventory-3 (NEO-PI-3), a more readable version of the Revised NEO Personality Inventory (NEO-PI-R), which showed good psychometric properties across cultures. Aggregate scores were generalizable across age and gender and showed convergence with culture-level scores from previous studies of self-reports and observer ratings of adults. Non-Western cultures tend to score slightly lower on a dimension related to Extraversion. Further, aggregate scores of adolescent ratings were unrelated to national character stereotypes, consistent with previous research that challenge the accuracy of these widely shared beliefs. The multinational study includes systematic assessments of personality stereotypes of age groups and genders as well as nations. Personality stereotypes of age and gender groups were assessed in each of the 26 cultures (N = 3,323) using the National Character Stereotypes measure, which includes items for each of the 30 facets included in the NEO-PI-3. Participants rated either males or females in the age groups adolescent, adult, and old in their own country. We compared assessed personality stereotypes of different age groups with previously published self-reported and observer-rated personality at each of the age groups. Across cultures, adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. Results showed that stereotypes of age groups were remarkably accurate, with only minor variability, though personal stereotypes of any particular rater were less accurate than the aggregate stereotype of each age group. This pattern of findings suggests that the formation of age stereotypes may have culture-neutral origins. In the assessment of National Character Stereotypes, participants were asked to rate the personality of the typical member of their culture, as well as the typical personality of Americans. Across cultures, the rating of Americans warmth and competence was systematically related to the rater cultures GDP, such that wealthier countries rated Americans as more warm and less competent. Results were similar when raters own family income is used as the predictor. Findings were consistent with theories on the dimensions of social perception.